There are two parts you could mean by "convert".
MacOS has keyboard substitution tables built into it that can change your keyboard to many different layouts, all Romance languages and even non-Roman writing systems.
The other part is the graphics on the keys. If you are an experienced touch typist, just place a printed keyboard map somewhere near your computer.
If you hunt an peck, as I do, you may need to put some labels on the keys, or use a sharpie marker. If you suffer from too much money, you could pay Apple to change out the keyboard with one that has the keycaps you prefer.
French notebook:
British Notebook:
from:
How to identify keyboard localizations - Apple Support
.